Although sexual psychophysiology has made great strides over the past few decades, the progress made has not been accompanied by much effort to integrate research findings or to stimulate methodological and theoretical discussions among researchers. Yet this new research area has the potential to make substantial contributions to understanding a wide range of phenomena, including the spread of HIV/STIs, sexual "addiction" or compulsivity, the use (or nonuse) of birth-control methods, sexual infidelity, and aggressive sexual behaviors. Psychophysiological methods can assist in the exploration of the underlying psychological, physiological, and affective processes, and, perhaps more importantly, how they interact. In this volume, editor Erick Janssen brings together wide-ranging essays written by an authoritative group of researchers, representing the cutting edge of sexual psychophysiology.